Super cool project! I really hope to see it come to fruition! I do think the dash mechanic could be improved (such as holding dash while on a wall and jumping results in a jump-dash, like in Mega Man X), but I like this a lot. One major issue though. I am not sure why, but I managed to freeze the game (requiring relaunch I think). I was in a segment on Doremy's stage, where there are a lot of Kedamas all shooting at you (after the P powerup and also a screen flash, I think near the end of the stage). I got hit and picked up a big healing item in close succession (possibly on the same frame), which caused the game to freeze. I was streaming it on Discord at the time, but I doubt that affected it. Attached is a screenshot. It seems that it still responds to inputs (pressing dash makes something pop up). I thought you may want to know this. Very nice game though!
It's not, and it can't happen anywhere else in the game. It's caused by the fact that collision check with the item happens before the game clamps Reisen's position, causing this to happen: you pick up the item -> game pauses -> game moves Reisen away from the item -> games stays frozen and no health is added. This happens because the code for health regeneration is in the item's collision event.